In procurement auctions, auction frequency and transaction volume per auction have been analyzed as important factors in determining auction performance. However, there is no empirical study on the effect of auction frequency and transaction volume in procurement auction. Current studies mainly focus on bidder behavior analysis and new system design in procurement auction. In the study, we analyze the effect of two factors on relative winning price empirically by using real auction data from MRO procurement outsourcing company in Korea. From the results, we find the winning price is lower when the frequency of auction with same item category is lower. The low frequency of auctions means participating bidders have limited information of previous auctions and they bid their best price to win the current auction due to less opportunity of reopening the auction in near future. The larger purchase amounts of MRO items didn’t results in lower winning price, contrary to our hypothesis. The possible reason is that the price of MRO items already reflects the economy of scales and the increased volume per auction do not cause the further discount of MRO items from the auction.